"I have a confession to make," he told politics.co.uk. "I do take the occasional puffs of cigarettes myself.

"I understand that if you do, the days of sitting in a pub drinking a pint and having a cigarette is something you feel very attached to."

But the Liberal Democrat leader insisted the ban conformed to his liberal philosophy.

"One of the first principles of a liberal is that you allow people to do what they want as long as it doesn't harm others," he said.

"Smoking is one of those classic examples where it's not a harm-free activity because it harms others around you and therefore I struggled with it a bit, but I voted for the smoking ban and I wouldn't seek to reverse it or dilute it."

The Lib Dem leader is not the first politician to admit to retaining a love of smoking, even if election strategists are stringent in making sure politicians are never photographed with a cigarette.

President Barack Obama notoriously struggled to quit smoking during his presidential campaign, with photo agencies desperately trying to get an image of the future president smoking.

The fashion is for politicians to project an image of health and vitality, hence the recurring photoshoots of David Cameron and, recently, Gordon Brown, jogging.

Across the Channel, President Sarkozy went out for a jog on his first day in the Elysee Palace.